Gauge



Sept. 2.1, 1937. `F. H. MARKwlcK @AUGEl Filed Oct. 16, 1934 l :inventor Gttomeg Patented Sept. 21, 1937 UNiTED sTATEsf PATENT. oFFlcE Frederick H. Markwick,

Dayton, Dhio, assignor to Shemeld Gage Corporation, Dayton, Dillo, a

corporation of Ohio application cerebel- 1s, 1934, sei-n1 No. '148,513 4' claim. (ci. sa-'rzsi This invention relates to tools, and more particularly to tool members 'of the character that in service repeatedly interengage other members.

One of the principal objects of the invention is 4the provision of a tool member of simple construction-incorporating an applied hard metal surface coating of such character as to effectively withstand the deteriorating effects of continued use.

Another object of the invention is the provision of a tool member of the character referred to having an electro-deposited hard metalI coating which covers the 'engaging face of the tool member and whichterminates .on the entering 4end of the tool member in abutting relationship with a shoulder formed thereon'.

Another object of the invention is the provision of such a tool member in which an offset is provided on the entering end for accommodationof a continuing lip of the hard metal coating; the

offset 'being of such proportions as to permit finishing the end of the tool member flush without reducing the lip to objectionable thinness.

Other objects ,and advantages of the invention wil1'b`e apparent from the following description,

the accompanying drawing, and the appended claims. 1 The application of ahard metal coating to the wearing surfaces of tool members such as die punches, gauges, and the like has been resorted to asa measure of economy. The desirable quality of hard metal, such as chromium, in resisting weara when applied to tool members of the character that are repeatedly interengaged with other members during service is but one factor in prol viding for economical usage of such tool members. In addition, a tool member incorporating an electro-deposited hard metal surface coating may be}readily reoperated by a renewal of the A surface coating yat but a fraction of the cost of the replacement value of the tool member. lThis is particularly true in the case of die punches, gauges and the like which, because ofthe quality of material used and the close limits of accuracy towhich such tools must be held, are costly toproduce.

'I'hereis, however, another factor to be' con- AY sidered. 'Unless the hard metal coating `is applied in such amanner as to resist removal as by chipping or flaking the reoperation may be required so frequently that more economical usage .will be afforded by un-coated tool members having no reoperation value.

The problem, therefore, is to apply the coating 55 in such a manner that it will effectively resist rethe steel plug part is nnished undersized with re- .tinues onto the entering face of the gauge to form moval by chipping or fiaking as a result of repeated engagement with other parts. In the case of a punch such chipping or flaking will render the punch useless for proper engagement with a die, while inthe case of a gauge such a con- 5 dition will not only render the gauge inaccurate but in addition may damage the work piece by scratching or scoring. I 1

The present invention contemplates a construction incorporating an electro-deposited hard 10 metal surface of such character that it will enectively resist removal by chipping or flaking. A suitable uniform depth of coating is assured on those portions of the tool member which conv tact the matingparts in service, and the coating 15 is such that it is free from thin overlaps that may readily flake off and thus adversely affect the expected useful life of such a surface coating. In addition, the practice of this inventiompermits the application of an electro-deposited coating of 20 such character that only the wearing surfaces of the tool member are coated, this making for fur- .ther economy.

It has been mentioned that a hard metal coating may be applied according to this invention to 25 punch gauges and like tool members which inl service repeatedly-engage other parts. lIt is believed that the full field of usefulness will be `clearly apparent from a consideration of but one form of application, andthe invention is there- 90 fore disclosed as applied to a plug gauge.

Plug gauges havewidespread usage for gauging the size of the annular openings in work pieces. In the entire field of gauging, including very elaborate equipment for accurately gauging to extremely Aline limits, plug gauges may be re-l garded as being relatively inexpensive. However,

these gauges do represent an investment of such` v value that any meansof increasing their usefulv life within cost limits favorably commensurate with the initial cost is of advantage. Applicant, by applying a durable hard metal coating of such character as to effectively resist removal and. wear in service, materially adds to the normal useful life of a plus gauge, and affords further economy by providing a gauge that may be readily restored to its original dimensions and usefulness.

In the initial processing of a plug gauge according to this invention the gauging face of spect to a desired diameter, andY is subsequently increased in-size by plating thereon a coating of hard chromium. The chromium coating is not limited to the gauging surface alone but conthereon a ring-like lip of chromium that is integral with the gauging surface. To insure an adequate thickness of chromium on the gauge as well as to avoid the termination of the coating as a thin overlapping layer which may readilyy flake oif and thus present to the workpiece sharp Jagged edges that will adversely affect the gauging operation, the chromium lip occupies an offset in the gauge end which extends inwardly from the junction with the gauging surface. In the case of a ring gauge the chromium coating likewise covers the gauging surface and extends as an integral lip onto the entering end of the gauge. When applied to a punch the chromium coating covers the punch part which interengages the die and extends as a continuing lip onto the entering face of the punch. The cutting edge of the punch therefore is of hard chromium which also extends onto both faces from the working edge.

In the drawing, which discloses a preferred form of the invention,-

Fig. 1 is a sectional view taken on the axis of an unflnishedgauge plug;

Fig. 2 is an end elevational view of a gauge plug upon which the chromium coating is applied but which has not been processed to the finished form;

Fig. 3 is an enlarged fragmentary sectional view as indicated at 3 3 of Fig. 2; and

Fig. 4 is a view of the ilnished gauge which is shown partly in section for clearness of illustration.

To refer now to the drawing, in which like characters designate like parts in the several with the axis of support.

views thereof, there is shown a. plug part I0 having an undersized surface II. One end of the gauge is provided with a tapering extension I2 for application of a handle I3, and the other end I4, referred to as the entering end, stands transversely to the gauging face I I.

Centering holes I6 are provided in the gauge ends as a means of support during the processing of the gauge. As a plug gauge, to be effective as a gauge, must be of uniform diameter throughout the extent of its gauging surface and must be capable oi being finished to a desired degree of. accuracy, it is essential that the centering holes I6 be maintained in true axial alignment so that when the plug is re-mounted on the centers dln'ing successive stages of the processing the gauging surface will valways be concentric ished to'he desired dimension without reducingV the chromium coating to an objectionable thinness. 'Ihe finished chromium layer is of the order of .003".

As mentioned above, an offset is provided onY the entering end Il which also receives a coating of chromium, this offset I8 extending inwardly toward the gauge center line from the junction of the end face with the gauging face. The offset Y has a depth in the direction of the gauger axis of the order of .005, and a width'extending toward the gauge center of the order of t/s". In the drawing the inner limit of the odset is deilned by the shoulder I9. 'I'he shoulder is shown extending transversely to the gauge end face. The shape or contour of the shoulder may vary somewhat without departing from the spirit of the invention as its purpose is to define a recess lationship with the plug end face.

'or o'set which, when filled with the chromium coating that is subsequently machined to a smooth surface flush with the remainder of the gauge end, will obviate any thin overlapping surface of chromium that may flake off during service and so destroy the usefulness of the gauge. Instead, by providing the offset, the chromium coating continues for the extent of the gauging surface and onto the entering end as a layer of substantially uniform thickness which terminates at the end of the lip in abutting re- As is subsequently described, during the plating process the chromium may form on parts of the gauge end in a thin overlapping layer but this, however, is removed in finishing the gauge so that there are then no portions of the plating in which overlapping edges are exposed, or in which the chromium is of such thinness that iiaking of the chromium coating may occur.

In the application of the chromium plating to the gauge the hard surface metal is deposited only on desired parts of the gauge by the use of a cylindrical anode which, in the plating bath, stands concentrically with respect to the plug axis. By the use of a cylindrical anode the hard metal is applied to the gauging 'face as a coating which is substantially uniform in thickness except adjacent the junction of the gauging face and entering end, indicated at 20, where the applied metal'tends to build out to a larger diameter than on the remainder of the gauging face. Further, the thickness of the hard metal coating on the entering end tends to taper off to a degree that the entire end face is not covered. 'I'he extent of end coating follows generally an irregular line as indicated at 22 which, as shown, does not extend to the plug center I6. 'I'his is an advantageous method of coating because it prevents the chromium surface layer from entering the centering hole, and thus prevents the possibility of shifting the center for subsequent processing operations on the center, which might easily result from an uneven coating of chromium o n the surface of the centering hole. 'Ihe chromium coat does, however, extend inwardly on the end an amount suillcient to fili the offset I8 and to extend over the offset shoulder I9 as indicated diagrammatically in Fig. 3.

Following the application of the chromium the plug is again mounted on the centering holes I6 and is further' processed to reduce the gauging face to the desired diameter. Owing to the irregularity of the hard metal thickness, particularly desired diameter which is indicated by the dotted line 25 in Fig. 3. The end face I4 is likewise 1inished and is preferably ground to the elevation of the part 26 of the end face which continues in from the offset. 'Ihis end finishing removes all the chromium from within the limits of the ring or face 26 defined by the shoulder I9 but does not objectionably reduce the thickness of the lip which illls the offset and which, in finished form, will have a face as indicated at 2l in Fig. 3; During the processing of the gauge before applying the chromium coat the junction or edge 20 is preferably ground or stoned sufficiently to break the sharp corner. This same short radius may be formed at the edge on the chromium coating to facilitate entering the gauge during a gauging operation.

'I'he provision of an offset on the entering end adjacent the gauging face permits a pleasing iinish on the gauge end in that the plated'lip shows asa well deiined annular ring that is concentric with the centering hole. The pleasing appearance however is quite secondary to the utility afforded by this construction. By continuing the chromium surface coating onto the entering end piece.

of thegauge, rather than restricting the chromium coating to the gauging surface alone there is no exposed plated edge which may flake off asa result of ,repeated engagement with the work It is thought that it is now clearly apparent that the hard metal coating ofl `this invention is such as to aiord economical processing, and is such as to' effectively resist deteriora.-

tion other than as a result of natural wear. It is believed also that it is clearly apparent that the construction is equally Well adapted to punches, gauges and. like tool members of thecharacter that are required yto repeatedly interfit other members. In any usage the toolmember edge, which is subjected to most severe wear, is supported by a well anchored coating extending in two directions from the edge. The coating is of suitable depth to resist flaking or chipping atlall points throughout its extent. The terminating edge of the lip stands in abutting relationship with an abrupt shoulder'so that a ilush end face vis afforded that is free of thin overlying'port'ions of plating that result in flaking. And, as pointed out above, these advantages obtain in a construc- 'tion that is.economical in that but 'a relatively small part of the entering end of the tool member' need be. coated. In the case of large gauges or punches this saving isl an item of considerable.

value.

While the'method and articles herein described constitute preferred embodiments of the invention, it isvto be understood that the inventionis not 4limited to the precise method and articles,

and that changes may be made therein without departing from the lscope of the invention which is defined `in the appended claims.

What isclaimed is:

1. A tool member* of the character described vadapted for engagement` with anothermember,

said tool member comprising av steel body part having a side and a transverse entering end, theentering end having-an oiset extending inwardly from the side and terminating in an abrupt shoulder, the ois'et having a depth of theorder of .005V and having a substantialface width, and an electro-deposited chromium coating of the order of .005" in thickness on the body covering the side and providing a gauging surface and tion of the wall and end face, andan electro-deposited hard metal coating covering the said wall and'forming a gauging face thereon and continuing onto the end face'and terminating at the remote portion that stands outwardly.

3. A gauging device of the character described adapted for engagement with a member to accurately-determine a size relationship, said gauging device comprising a metal body part having a side wall for provision of a gauging face and 'having `a transversely related iiat entering end face formed with an oiset extending from the side wall and terminating on the face in an abrupt shoulder, and an electro-deposited hard metal coating 'covering the side wall as a gauging face and covering the oilset portion of the end face as a hard metal lip continuing from the side wall and terminating at the shoulder flush with the at entering face. 4

.4. A gauging -device of the character described adapted for engagement with a member to accurately determine a size relationship, said gauging device comprising a metal body part having a wall for provision of a gauging face and having a transverse end face, the end face of said bodyv part having a recessed portion, and angelectrol deposited hard metal coating covering thesaid wall and forming aY gauging face thereon, said coating. continuing from the gauging face onto the end face and terminating in engagement with said recessed portion.

FREDERICK H. MARKWICK 

